/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.transformation.dag.column.binary;

import org.apache.iotdb.db.mpp.transformation.dag.column.ColumnTransformer;
import org.apache.iotdb.db.mpp.transformation.dag.util.TransformUtils;
import org.apache.iotdb.tsfile.read.common.block.column.Column;
import org.apache.iotdb.tsfile.read.common.block.column.ColumnBuilder;
import org.apache.iotdb.tsfile.read.common.type.Type;
import org.apache.iotdb.tsfile.read.common.type.TypeEnum;

public abstract class CompareBinaryColumnTransformer extends BinaryColumnTransformer {

    public CompareBinaryColumnTransformer(
            Type returnType, ColumnTransformer leftTransformer, ColumnTransformer rightTransformer) {
        super(returnType, leftTransformer, rightTransformer);
    }

    @Override
    protected void doTransform(
            Column leftColumn, Column rightColumn, ColumnBuilder builder, int positionCount) {
        for (int i = 0; i < positionCount; i++) {
            if (!leftColumn.isNull(i) && !rightColumn.isNull(i)) {
                boolean flag;
                // compare binary type
                if (leftTransformer.getType().getTypeEnum().equals(TypeEnum.BINARY)) {
                    flag =
                            transform(
                                    TransformUtils.compare(
                                            leftTransformer.getType().getBinary(leftColumn, i).getStringValue(),
                                            rightTransformer.getType().getBinary(rightColumn, i).getStringValue()));
                } else if (leftTransformer.getType().getTypeEnum().equals(TypeEnum.BOOLEAN)) {
                    flag =
                            transform(
                                    Boolean.compare(
                                            leftTransformer.getType().getBoolean(leftColumn, i),
                                            rightTransformer.getType().getBoolean(rightColumn, i)));
                } else {
                    double left = leftTransformer.getType().getDouble(leftColumn, i);
                    double right = rightTransformer.getType().getDouble(rightColumn, i);
                    if (Double.isNaN(left) || Double.isNaN(right)) {
                        flag = false;
                    } else {
                        flag = transform(compare(left, right));
                    }
                }
                returnType.writeBoolean(builder, flag);
            } else {
                builder.appendNull();
            }
        }
    }

    @Override
    protected void checkType() {
        // Boolean type can only be compared by == or !=
        if (leftTransformer.typeNotEquals(TypeEnum.BOOLEAN)
                && rightTransformer.typeNotEquals(TypeEnum.BOOLEAN)) {
            return;
        }
        throw new UnsupportedOperationException("Unsupported Type");
    }

    protected int compare(double d1, double d2) {
        return Double.compare(d1, d2);
    }

    /**
     * transform int value of flag to corresponding boolean value
     *
     * @param flag
     * @return
     */
    protected abstract boolean transform(int flag);
}
